1. Field of the Invention
The invention relates to single use, disposable, personal cleansing products, and more specifically to an article with a distinct active zone.
2. Description of the Related Art
Personal cleansing products have traditionally been marketed in a variety of forms such as bar soaps, creams, lotions, and gels. These formulations have attempted to satisfy a number of criteria to be acceptable to consumers. These criteria include cleansing effectiveness, skin feel, skin mildness and lather volume. Ideal personal cleansers should gently cleanse the skin or hair, cause little or no irritation, and not leave the skin or hair overly dry after frequent use. Personal cleansing products have also been combined with water insoluble substrates to improve convenience to the user.
Visual indicators such as color has been used to denote the distinction of active zones and the depletion of active substances associated with various substrates. U.S. Pat. No. 4,311,479 titled Method of Indicating the Presence of an Impregnant in a Substrate, issued to D. Fenn et al. on Jan. 19, 1982 discloses a method for detecting the presence of an impregnant, e.g. an antimicrobial composition in a cloth to provide visual evidence of the continuing activity of the impregnant. Portions of the impregnated cloth are dyed with an indicator dye which bonds preferentially to the antimicrobial composition so that when the antimicrobial composition is exhausted, the dye will disappear from the cloth.
U.S. Pat. No. 4,678,704 titled Impregnated Substrate Incorporating An Indicator Dye issued to A. Fellows on Jul. 1, 1987 discloses an impregnated fabric material that has been bonded to an active cationic impregnant, and an anionic indicator dye in combination with a further cationic component also applied to the fabric material, wherein the dye bonds to the second cationic component more readily than to the fabric The second cationic component competes with the impregnant for bonding to the dye. In the case of a wiping cloth, the dye acts as an indicator the disappearance of which indicates depletion of the active component with use.
U.S. Pat. No. 4,987,632 titled Wiping Article, issued to Rowe et al. on Jan. 29, 1991 discloses a substantially dry-to-the-touch wiping article which is suitable for use in cleaning soiled surfaces in the presence of water, and that has a water absorbent substrate impregnated with a detergent active compound and sandwiched by a moisture barrier. The moisture barrier is applied to the article's surface in the form of a design pattern, decorative feature or logo. The detergent active material or the moisture barrier can comprise a water-soluble dyestuff or colorant and a perfume, the disappearance of which can signal exhaustion of the material. DT 2625176A to Schickdenz, published in December 1977, discloses a wiping cloth with an active detergent distributed in a pattern such as in the form of lines, etc., onto the cloth and separated from the untreated areas of the cloth by a hydrophobic substance or boundary strip. U.S. Pat. No. 4,601,938 to Deacon et al. issued on Jul. 22, 1986 discloses a wet wiping article impregnated with a liquid composition such as a skin treatment composition in specific areas where migration of the liquid is prevented by means of a repeating pattern of liquid repellant barriers. However, there is no disclosure or suggestion in either Rowe et al., Schickdenz, or Deacon et al. of the effect of carrier solvent on migration or bleeding of active components in the article to adjacent zones when no liquid or moisture barrier is used.
U.S. Pat. No. 5,293,648, titled Tag For Visually Indicating Loss Of A Protective Agent, issued to R. Finley on Mar. 15, 1994 discloses an indicator tag that is made from a fabric dyed with at least one dye to impart to the piece of fabric a predetermined initial color which indicates that the chemical treatment agent on the textile article is effective. The dye has a chromophore which is susceptible to degradation by reagents which would destroy the effectiveness of the chemical treatment agent so that exposure of the indicator tag to such reagents causes the indicator tag to change from its predetermined initial color to another color, thereby indicating a loss in the effectiveness of the protective chemical treatment agent on the textile article.
PCT publication no. WO 01/54661 published on Aug. 2, 2001 discloses a 2 layer cleansing article with therapeutic benefit components disposed adjacent to one layer of the article in a specified concentration and distribution pattern (FIGS. 6 and 7) and isolated by a reservoir seal from the remainder of the article. However there is no disclosure or suggestion of the effect of carrier solvent on therapeutic agent bleeding in the article to adjacent zones where no reservoir seal is used.
U.S. Pat. No. 6,231,719 to Garvey et al. issued on May 15, 2001 discloses a tissue product coated with a skin moisturizing formula in a stripewise pattern wherein the concentration of the skin moisturizing agent varies between the adjacent stripes. The skin moisturizing formula is a solid at room temperature and is coated onto the tissue product at elevated temperatures as a liquid melt. The skin moisturizing formula later solidifies onto the surface of the tissue.
Surprisingly, it has been found that wiping articles may be produced that contain a pattern of active zones containing one or more benefit agents selected from nondetergent active agents, conditioning agents, aesthetic agents or a mixture thereof for treating the skin or hair and further containing a critical range of carrier solvent sufficient to facilitate the transfer of the abovementioned agents from the active zone to the user when the article is wetted with water but below a level causing bleeding across the article interface of the agent(s) into adjacent non-active zones in the wiping article. It is a feature of the inventive wipe that the effective diffusion rate of the carrier solvent across the wipe article interface into the adjacent non-active zone is substantially identical to its diffusion rate adjacent to the interface, or in other words within the active zone. This is in contrast to prior art wiping articles that have liquid or moisture barriers separating the active zones from the non-active zones. It is another feature of the present invention that the coating composition containing the benefit agent is flowable at room temperature prior to any drying or removal of excess carrier solvent. Advantageously the coating composition has a melting point below 30 C. Optionally the active zone may contain a visual indicator associated with the benefit agent(s) whereby the disappearance or transformation of the indicator would signify the transfer of the benefit agent to the user. In another embodiment of the inventive wipe, specific active materials may be used as benefit agents that are either 1) unstable in a specific solvent mixture, such as vitamin C in an aqueous medium, or 2) are not compatible with other ingredients in a mixture such as salicylic acid with a surfactant, and the like. These agents may be separately coated onto the wiping article with a carrier solvent that does not degrade the specific active material or in a compatible blend of carrier solvent and other ingredients as the case may be. In this regard, a sufficient quantity of carrier solvent is used to solvate or disperse the active material so that the material will be rapidly released when the article is wetted with water and transferred to the skin or hair of the user. Advantageoulsy, the fact that the coating composition is a liquid at room temperature that does not require heating during the coating process is useful in incorporating heat labile benefit agents in the inventive article. The bleed resistant properties between adjacent active and non-active zones of the inventive wiping articles is conveniently expressed as the Dynamic Active Zone Depletion percentage described below.